Electrokinetic pumps provide for liquid displacement by applying an electric potential across a porous dielectric media that is filled with an ion-containing electrokinetic solution. Properties of the porous dielectric media and ion-containing solution (e.g., permittivity of the ion-containing solution and zeta potential of the solid-liquid interface between the porous dielectric media and the ion-containing solution) are predetermined such that an electrical double-layer is formed at the solid-liquid interface. Thereafter, ions of the electrokinetic solution within the electrical double-layer migrate in response to the electric potential, transporting the bulk electrokinetic solution with them via viscous interaction. The resulting electrokinetic flow (also known as electroosmotic flow) of the bulk electrokinetic solution is employed to displace (i.e., “pump”) a liquid.
The electrokinetic element, which generally includes the porous dielectric media or electrokinetic material laminated in a polymer, is a key component of the electrokinetic pump. The electrokinetic element is bonded within a chamber of the pump and separates the pump body into two chambers. If the electrokinetic material is charged, pressure and fluid flow can be generated by applying a voltage at the two sides of the electrokinetic element. It is critical to the operation of the electrokinetic pump that the electrokinetic solution flow through the electrokinetic element without leaking around the exterior of the electrokinetic element or between the electrokinetic material and the laminate. One known approach to making the electrokinetic element is by laminating electrokinetic material between two pieces of plastic using a temperature sensitive adhesive. There are various drawbacks to this technique. For example, the adhesive often flows into the inlet and outlet ports of the electrokinetic element and must be manually removed. In addition, several layers of adhesive must be used, increasing the complexity and cost of the process. The quality of the adhesive bond also depends on time, temperature, pressure, and geometry, making the lamination process difficult to control.
Accordingly, there is a need for improved methods for preparing an electrokinetic element.